<html>
<body onload="document.querySelector('colgroup').style.borderLeft='6px solid green';">
  <table style="border-collapse: collapse;">
    <colgroup></colgroup>
    <tbody>
      <tr></tr>
    </tbody>
    <tbody>
      <tr></tr>
      <td></td>
      <td colspan="2"></td>
    </tbody>
  </table>
</body>
</html>
